SPC-807 change the thread report plugin to do an in-JVM dump

Conflicts:
	features/system-report/src/main/java/org/opennms/systemreport/system/ThreadReportPlugin.java
	features/system-report/src/test/java/org/opennms/systemreport/system/JavaReportPluginTest.java
	features/system-report/src/test/java/org/opennms/systemreport/system/TopReportPluginTest.java